


The Science of Forward Momentum

by thisprettywren



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Community: hc_bingo, M/M, Time Loop
Language: English
Status: Completed
Published: 2011-08-10
Updated: 2011-08-10
Packaged: 2017-10-22 11:12:10
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,797
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/237433
Author URL: https://archiveofourown.org/users/thisprettywren/pseuds/thisprettywren
Summary: <blockquote class="userstuff">
              <p>Sherlock understands the impossibility of second chances.</p>
            </blockquote>





	The Science of Forward Momentum

The first time he walks into the pool and sees John wrapped in Semtex, it takes the space of several carefully-controlled breaths to shift the scene from _impossible_ to _improbable_ in his own mind.

(It does get easier—more believable—after that.)

The first time, though, it’s still impossible. It steals the air from his lungs.

He says the only words that come to mind and they sound incredulous, betrayed, accusatory: “You went to get the shopping.”

John simply blinks at him before saying, in a voice not entirely like his own, “This is a turn-up, isn't it, Sherlock.”

And oh, it was, it really _was_.

When Moriarty reveals himself, Sherlock has never felt so stupid; when John nods at him, giving him permission to shoot the vest, he's never felt so furious.

He thinks, _Game over_ , and doesn't have the words for what he feels after that.

It’s the only possible option; he sights along the barrel of the pistol, squeezes the trigger. He doesn't flinch.

 

 

There's a noise he feels more than hears; a hard rush of air as everything around them goes very, very bright, then absolutely dark.

 

 

 

 

 

 

 

 

He's standing in the art gallery, heart pounding like he's just run a marathon, thoroughly disorientated.

" _John_.” His voice is strange, breathless, scarcely recognisable as his own, and John gives him an odd tense look just as the pink phone begins to ring in his hand.

Sherlock stares down at it—blinks, breathes—and connects the call with a disconcerting sense of deja vu.

"It's a fake," he says, feeling dazed but still able to remember. It’s impossible that he remembers; just as impossible that he wouldn’t. Silence on the other end of the line; harsh urgency in the lines of John's face, Lestrade's. "It's a fake," Sherlock says again.

He looks at the painting; last time, it had been painted on the wrong sort of material. This time the material is right, so it must be something else that's wrong, but he can’t see it.

Through the receiver against his ear, there's the sound of a child crying, then nothing, and all Sherlock can think is _oh_ , because John is standing next to him. John is _there_ , though Sherlock has just watched him die, and there's nothing in his rational mind that understands it.

Sherlock has never believed in second chances, but it seems he's going to get one.

 

 

That night he takes the only possible option and kills them both for the second time.

 

 

 

 

 

 

 

He's standing in the art gallery, heart pounding, furious and frightened to the hard edge of panic.

The phone is in his hand; when it rings, he doesn't answer it.

"I'm not playing these games anymore," he says, face turned upward, half-shouting, ignoring the voices clamouring around him. "Do you hear that? I'm not playing anymore."

He doesn't have to watch John die that night, but when they get the news about the boy the look of shattering disappointment on John's face is so very much worse that Sherlock doesn’t take that route again.

 

 

 

 

 

 

The next time it's the signature on the painting, and Sherlock sees it with two seconds to spare. The time after that he doesn’t have the space in his mind to work it out and harangues Mrs Wenceslas into telling him, which is against the rules.

Though John insists it isn’t his fault the child still dies and Sherlock still doesn't know how to get them out of that bloody pool, except in body bags, doesn’t know what he has to do to prevent the world around them from going blood-red and bruise-dark.

He sends John to investigate the memory stick again and again, hoping to buy himself time to think, to do something different. Nothing ever works, not even handing it over to Mycroft, though he tries that as well.

It take him three more tries to figure out that the memory stick is important, or at least useful, in the greater scale of things. After that he still sends John to investigate, goes through the motions. It buys him time to himself, time to think, and he’s rewarded with the admiration on John’s face as he solves it unerringly, time after time. It’s a hollow victory, false comfort, and he mocks himself for it even as he holds it close.

They always end up at the pool, in the end, John wrapped in explosive paste under that hateful parka and Sherlock, square-shouldered, wrapped in defeat.

Each time John understands, forgives him, and it makes it all worse.

“You couldn’t have stopped it,” John whispers to him in the quiet space after the snipers finish with them the first time, while his blood is still pooling around him against the harsh tile. Sherlock’s chest is burning, his legs a dull, distant ache.

“Yes I could,” he whispers back, but John is already gone.

 

 

 

 

 

 

Death is the logical, inevitable result of life. Sherlock had always supposed that meant he wouldn’t mind it, much.

( _If it were mine alone_ , he thinks, but that doesn’t quite feel right, either.)

It’s the repetition that’s tearing him to pieces.

John always tells him to run (shows his hand, again and again; opens his chest and shows that, too) and once--only once--Sherlock does. Gives in to a moment of absolute crushing cowardice because he knows he simply cannot stand to see it happen again.

The world explodes behind him while his feet are still skittering down the steps to the street. The force of it knocks him flat, face to the pavement.

At the end of that night Sherlock is bloody, bruised—ruthlessly alive—and John is gone.

It's the only time ending up back at the gallery feels like a gift.

 

 

 

 

 

 

"Of course he's the boy's father!" It’s a pointless indulgence, the bits of his mind that should be useful worn threadbare with repetition, blank and numb.

John looks up from his laptop and gives him a sideways glance, amusement tugging at the corner of his mouth. "How can you know that?”

 _I've seen it before_ , Sherlock thinks, but of course he can't say it, mumbles something about the man's jeans.

"Amazing," John says, and it’s so freely given that something inside Sherlock shatters.

_Not nearly enough, for all that. I don't know how to save you._

And, because he can't say that, Sherlock tries something new. "I think we're out of milk." His voice sounds like it's coming from somewhere very far away. "I'll go get some."

"Really?" John's face brightens and Sherlock has hope, just for a moment, that he's solved it. He'll go out and John will stay home and maybe, maybe--

But when he gets back, shopping bag in hand, the flat is empty.

 

 

 

 

 

 

Moriarty may have stolen John's voice, but they don't need words to speak to one another, not anymore.

John's face is a crime scene of its own, worn and resigned and impossible not to read. _We're going to die today, Sherlock._

Sherlock answers him as the red dot appears—again, as always—over the center of John's chest.

_Yes, John. I know.  
_

 

 

 

 

 

 

He buys the milk (and the beans) the next time, too, and even brings them back to the flat, just on the principle of the thing. An empty gesture of defiance.

When the red light begins to dance across John's heart, Sherlock can’t look at him any longer. He twists his wrist and raises his arm to press the pistol against his own temple--

"Oh, Sherlock, you don't want do that," Moriarty says.

"Oh, I really _do_."

\-- and feels a moment of absolute calm as he squeezes the trigger.

 

 

 

 

 

 

He turns the gun on himself several more times; Jim, more times than that. He knows after the first attempt that it won't work, but he also knows it doesn't matter, and it's madly satisfying. It feels absolutely right and lovely, in fact, for that split second before the snipers react and everything goes bright with pain.

"You got him," John whispers once, the words bubbling thick and crimson over his lip. Sherlock thinks he manages a smile in answer.

 

 

 

 

 

 

He never aims the pistol at John. The one unacceptable outcome.

 

 

 

 

 

 

 

Sherlock is sure he's never felt more tired.

"We're out of milk," John says, closing his laptop, and Sherlock knows it's useless but he has to try.

"Stay here, John.”

John turns to him and chuckles, a warm, indulgent sound. "I'm freezing my bollocks off in here," he says, "and if I'm going to _keep_ freezing my bollocks off, I need some milk to put in my bloody tea," and he's gone.

He doesn’t come home.

Sherlock can't bring himself to go to the pool, that night. The phone rings and rings and he doesn't answer.

 

 

 

 

 

 

The sound of the child's voice on the phone makes everything in Sherlock's body tense. He can't seem to get enough air to his lungs, and though he sees fairly quickly that the yellow in the paint is just a shade too dark the room is spinning by the time he disconnects the call.

"Hey, Sherlock, it's okay," John says, his face creasing into concern. There's a hand on Sherlock's shoulder and he turns his head to stare down at it; it's steady, the tan line on John’s narrow wrist faded to nothing. “It’s a sequence, right? The fifth pip. We’re nearly there.”

Sherlock doesn't laugh, or not exactly, and John's eyes go dark with worry.

"You just need a rest," he says. "Let's get you home."

They make it back to the flat and Sherlock doesn't send John to visit Mycroft, doesn't log onto his website, just curls up on the sofa and tries his very hardest not to think. And it almost works, for a while, until the inevitable _click_ as John shuts his laptop brings Sherlock to the inexorability of the present.

"I'll just go get some milk," John says.

It is, by all objective measures, simply _too much_. Sherlock likes to think of himself as having very few limits, but he’s just reached one, and rather abruptly, something dark and close-held inside him fracturing at the force of the impact.

He unravels his spine to look over his shoulder. “No, John. Stay here."

 _Cold. Tea._ He can see John's intention, his lips beginning to form around the words—because, while it’s the same for Sherlock it’s always, always new for him—and it just can’t happen, not again.

 _Stop him_. He stretches out a hand to John’s arm, grabbing at his wrist. Pulls him close. John blinks down at him, flat-footed and gaping.

"I just can't lose you again," Sherlock hears himself say, "not tonight," and has just a fraction of a second to note the frown of puzzlement that crosses John's face before it dissolves into understanding, the rapid shift of his features as he processes _him_ and _me_ and _yes_ —

(oh, John, clever John)

— and he’s crushing their lips together, fingers digging into John's shoulders, and John is leaning in, yielding to him, lips and tongue hungry and alive against Sherlock's mouth.

There’s never enough time; never enough of anything, even now.

"This is a turn-up," John says, his lips curled into a smile against Sherlock’s skin, and though the words send something painful and boiling through Sherlock's veins John's voice is warm with humour and something darker, with an inexorability of its own.

And there’s an instant, just the barest fraction of a second, during which Sherlock’s entire world tips sideways, when he goes from _not knowing_ to _knowing_. And it doesn’t matter how many times it happens again; there will always be this, a before and an after relative to this knowledge, and everything for Sherlock must now follow.

It feels like waking up, like remembering how to breathe, and with it comes a curl of icy fear that settles in the pit of his stomach, because what if—

— it only happens once; or

— John never remembers; or

— Sherlock never saves him, never saves _them_ ; and

— it would (will) be like losing him again (and again and again), in a whole new way.

 _No,_ he thinks, _I won’t, I can’t_ , but he can’t say that, not any of it, so Sherlock just smiles and hums an agreement and pulls him closer, as though he can hold him (them) there.

It feels like a long time later that they’re tangled together on his bed and Sherlock trusts himself to speak again, seeking the assurance John has given again and again.

“Do you trust me, John?”

John nods, that same little nod he’s seen countless times before, and it’s no less devastating for its familiarity, this time framed not against harsh tile but the soft surface of his pillow. Sherlock’s chest aches with the effort it takes to say the words, only these words and nothing else:

“Then stay here, just for tonight.”

Neither of them leave the flat that night. They pass it together while Sherlock listens to the distant sound of sirens and holds on desperately, hopelessly, breathing the air around John’s body.

 _Stay with me,_ Sherlock thinks as John’s limbs begin to loosen and grow heavy with sleep, _stay. Not again, not again, not again_.

 

 

 

 

 

 

He’s standing in the art gallery, the floor hard enough under his feet that it aches all the way up into his spine and through his chest. And John— John is looking at him with the same expression he’d had the time before, and the time before that, and there’s an ache there, too, because for Sherlock it’s _after_ and he may be used to knowing things others don’t but never anything like this.

Sherlock wants to reach for him (remind him, show him, _John_ ) but his phone is ringing and they don’t have time.

Somewhere between the van Buren supernova and the cab ride home it hits him, understanding sitting sharp and precise as glass in the front of his skull: if for John it’s still _before_ , then all Sherlock has to do is send him away. Let him go to keep him safe. Sherlock himself is harm’s way, and he can keep John out of it, still, if he doesn’t yet know. Sarah feels a hundred years in the distant past but she’s there, and John’s always been susceptible to suggestions when Sherlock is the one making them.

There may be a way to save them both, still; logically, he ought to make the choice for himself. He’s extraordinary, John says so (he knew it himself already); only one of him.

And yet. He’s lost either way (lost, indeed— _John_ ). Might as well salvage something from the wreck of him, the inevitable chaos he leaves in his wake.

He settles into his chair, pulls his coat tight around himself. Wants to leave John with something like happiness, if he has to leave him, so he shouts at the telly and jokes about a knighthood. In case it counts, in case it ruins everything: _Remember me as I am._

“You know, I’m still waiting.”

John’s voice is casual and though it stirs something warm and painful in his chest Sherlock is ruthless, doesn’t allow himself to give voice to any of the words crowded behind his teeth. Instead he averts his eyes and promises to get the shopping (those words the most difficult of all, somehow, an empty promise he knows he will fail to keep even as he makes it, even as he wants to make a different promise entirely). He shoves his hands in his pockets and watches John stand, walk to the door, watches it close behind him and still he says nothing because he absolutely _can’t_.

At least if he’s wrong he won’t have to live with it for long. Even so, if he stops to think about it he’ll crack and risk them both, pull John back in only to lead toward his own obliteration again. He pulls out his laptop instead, sets the familiar time, the familiar place, and then all that’s left to do is breathe and wait.

 

 

 

 

 

 

He steps through the door of the natatorium with something almost like triumph beating in his chest. He feels hollow and horrid and absolutely certain; he’s figured it out, he’s solved it, and John will be safe and if Sherlock never sees him again at least he never has to know. He’d consider it an act of selflessness if he were capable of such things, if it didn’t feel so much like victory to think of John waking up the next day, the assurance of it a counterweight to the loss he feels at the thought of everything he’ll miss.

He’s so blindingly sure that when John steps out of the shadows he can’t do anything but stare, breathing John’s name and blinking against the brightness of his ultimate disaster.

“This is a turn-up,” John says in that voice not his own, and Sherlock feels like his whole world has drained through the soles of his feet, his absolute failure a lead weight in his chest, because even if it’s all happened countless times before now it’s also happening _after_ , and though he knows it doesn’t count any more this time than it has any of the others it still hurts.

_We're going to die today, Sherlock._

He knows. He _knows_. Sherlock tries to keep the knowledge from his face because he doesn’t want John to see it, but when the red dot slides home on John’s chest he can’t stop his eyes from sliding closed.

Moriarty’s lilting, off-kilter cadence scrapes against his ears and Sherlock is so full of hate he thinks, for a moment, that there can’t possibly be room in his chest for anything else, but one glance at John (jaw flexed in determination, red dots dancing across his torso) is all the proof he needs that there’s space for so much more. He must not have a heart after all, he thinks; it must be hollow there, to make room for this impossible pressure, and John could probably make sense of it but there’s never enough time.

He doesn’t run when John tells him (though it’s a rational move it’s not even a question, not anymore); when Moriarty slinks away Sherlock rips the vest from him with fingers that won’t stop shaking and when John laughs he rubs the barrel of the pistol against his temple to remind himself that he can’t, absolutely cannot, release the words that sit so heavy against his tongue.

(In memory, John’s voice: _It’s not kinder, no,_ and Sherlock wants to tell him that it is, it really is, but this is _after_ and perhaps it’s simply that it’s all different, now.)

He knows what’s coming but he waits for John’s nod—the nod John has always given, every time they’ve been here, unfailing in his absolute trust; it’s Sherlock who’s failed and he doesn’t know what to do with that, but John has followed him and here they are—and yes, all of Moriarty’s words have crossed his mind because he’s heard them before, every possible permutation, and he drops his arm and sights along the barrel of the pistol and breathes and squeezes

 

 

and the world goes very, very bright and then absolutely dark.

 

 

 

 

 

 

 

 

The tumult of the explosion is followed by a thoroughly disorientating stillness, and it takes Sherlock the space of several long breaths to register that this is something new.

His own pulse is loud in his ears; he can hear other noises beyond that, distorted and muffled like he’s underwater. He takes a breath deep enough to hurt, a slow throbbing ache spreading outward from his spine.

His next breath jolts into his chest. _John_. He turns his head and blinks his eyes open but he can’t see anything beyond the shifting darkness left in his eyes from the blast itself. The air smells (feels, tastes) singed. He tries to shout but he gets a mouthful of dust and smoke and ends up coughing instead, the movement jarring the heavy pressure against his ribcage.

A moment of absolute cold fear: What if this is the time that counts, what if he’s got it _wrong_ —

Then there’s a hand on his shoulder, his throat, pressure against his jaw; a damp cloth, heavy with the smell of chlorine, filtering the grit from the air. He blinks until his vision clears enough to see John’s eyes. He’s holding a scrap of his shirt to his own mouth, and what Sherlock can see of his face above it is blood-red and bruise-dark.

“There you are,” he hears John say, the sound still muffled. Oh, obvious; percussive impact, attendant hearing loss. A logical consequence, a miracle of physics, and Sherlock would grab him and laugh at the beauty of it if his limbs didn’t feel so heavy.

John bends to push the rubble away from Sherlock’s chest and legs. There’s a thick coating of grey dust in his hair, and Sherlock has the nonsensical thought that this is what he’ll look like when he’s old. It’s an oddly comforting idea and he _does_ laugh then, a sharp flood of relief surging up his spine.

 _We made it_ , he thinks in disbelief as the air around them begins to pulse with approaching sirens.

John just looks at him, blue eyes creased in something halfway between concern and warm affection, and Sherlock can’t do anything but smile back. It’s clear that John doesn’t really understand. He can’t possibly. For him it’s still _before_ , and for just a moment Sherlock feels slightly dizzy with the gulf between them, the world around him tipping sideways yet again—

 

( _hands on his skin, distant voices and an odd shifting vertigo, and his vision fuzzes over with grey but he never loses track of John’s hand, curls his own fingers around John’s wrist until the distance becomes impossible; then he just holds with his eyes, stares at those steady fingers, the subtle upward curve of their promise_ )

 

— until it rights itself, abruptly, with the first jarring impact of the wheels of the gurney in the bay of the ambulance. Two things become absolutely, perfectly clear, each as vitally important as the twin currents of the blood in their veins: first, that if momentum has been restored it can never be _before_ again; and second, that John is sitting beside him, his bloodstained cheek curled into an exhausted smile, and doesn’t yet _know_.

And it’s the second one that, improbably, softens his own smile into something altogether warmer and more complicated, because they’re moving forward and away and if John doesn’t yet know that means this is something entirely new, and Sherlock gets to be the one to show him.

**Author's Note:**

> For my h/c bingo square "Time Travel Gone Wrong." See my card [here](http://thisprettywren.dreamwidth.org/19716.html#cutid1).
> 
> Originally inspired by [Ivy Blossom](ivyblossom.livejournal.com)'s captioning for [this gif](http://ivyblossom.tumblr.com/post/8597635094/johns-face-says-well-i-think-were-going-to), of all things. But OH, their faces.


End file.
